Of course, there is some truth in advertising. There's yeast in bread, but you can't make bread with yeast alone. Truth in advertising is like leaven, which a woman hid in three measures of meal. It provides a suitable quantity of gas, with which to blow out a mass of crude misrepresentation into a form that the public can swallow.
Dorothy L. Sayers (2012). “Murder Must Advertise”, p.86, Open Road Media